The invention relates to a pneumatic brake force producing device having at least one intake device for the surrounding air.
During the operation of the service brake, an air exchange takes place in the case of a pneumatic brake force producing device between the pressureless spaces of the pneumatic brake force producing device and the environment.
Systems are known which take in air directly from the environment, in which case special take-in elements hinder the taking-in of dust and/or splashing water.
When the surrounding conditions change, for example, the temperature of the surrounding air, the components of the brake force producing device adapt to the new surrounding conditions slowly.
If the taken-in air is, for example, warmer than the pneumatic brake force producing device, which happens, for example, when leaving a tunnel, there is the risk of a condensation of the air humidity in the pneumatic brake force producing device. This may lead to a corrosion within the pneumatic brake force producing device. This corrosion may result in operating disturbances or failure of the brake forcing producing device.
The present invention providing a device which reduces the danger of a condensation of the air humidity in the brake force producing device. The device is to be cost-effective and should require no maintenance.
The present invention is a pneumatic brake force production device for a vehicle having at least one intake device for taking in surrounding air. The at least one intake device has a heat storing container and condenser for condensing humidity out of the surrounding air. The condenser includes at least one pipe feeding or guiding the surrounding or intaken medium or air to the brake force producing device. In addition, at least portions or parts of the at least one pipe are arranged in a cooler zone or area of the container which, in a regular driving operation of the vehicle, is cooler than air-guiding parts of the brake force producing device.
The taken-in air is fed or sucked through the condenser into the pneumatic brake force producing device. In the parts of the at least one pipe (which pipe may hereinafter be called xe2x80x9cthe pipexe2x80x9d, xe2x80x9cthe pipingxe2x80x9d, xe2x80x9cthe coiled pipingxe2x80x9d and/or xe2x80x9cthe condenserxe2x80x9d) of the condenser which are situated in the cooler zone, the air guided in the pipe will be cooled. Since, at the same absolute humidity of the air, the relative air humidity of cold air is higher than that of warm air, condensation of the air will occur in the cooler zone inside the pipe. During the air flow through the pipe, the temperature of the air approaches the temperature of the interior surface or wall of the pipe. Since the air-guiding parts of the brake force producing device, in the regular-driving operation, are wanner than the pipe, the temperature of the air remains the same when entering the brake force producing device or it heats up. In this case, the relative air humidity remains the same when leaving the intake device or it falls as the temperature increases. Since the relative humidity is below the saturation point of the air leading to a condensation at this temperature, the risk of a condensation of the air within the pneumatic brake force producing device is considerably reduced. As a result of this simple construction, the brake force producing device of the present invention is cost-effective. Since it contains no movable parts or parts subject to wear, it is maintenance-free.
In the present invention, the pipe may be a pipe or a pipe system. The cross-section may be, for example, round, elliptical, rectangular polygonal, etc. The pipe may, for example, also comprise a duct or a hose or may be a combination of various elements.
The entire pipe may be arranged in the cooler zone or may, for example, be cooled separately or independently from just being in the cooler zone.
The condenser may be, for example, a pipe whose free end represents a condenser intake opening. The free end may terminate or end in the proximity of or form a heat-storing body which may be all or a portion of the container. For example, the heat-storing portion may be in the proximity of the bottom of the container which is open toward its top. Inside the container, the temperature profile of the air changes or adapts itself to the surrounding temperature from the top to a bottom of the container. Cool air layers situated at the bottom of the container act in a heat-absorbing fashion. The area of the highest condensation will then be the area of the free end of the pipe.
The slope or inclination of the pipe is, for example, greater than the maximal slope and/or the inclination of a line or travel path carrying the vehicle. As a result, condensate, which forms during flow through the pipe, can flow off through the pipe independently of the vehicle inclination. The risk of a condensate intake is thereby reduced.
A heat exchange surface or exterior pipe surface of the condenser toward an exterior or cooling medium is, for example, larger than an interior surface of the condenser toward the guided taken-in air or interior medium. Thus, on its exterior surface, the pipe can be maintained at a temperature of heat-storing body surrounding it, while the temperature of the air guided on the inside of the pipe may approach but be greater than the temperature maintained by the heat-storing body. The cooling medium may be air or another gas or a liquid.
The pipe may be made, for example, of a corrosion-resistant material.
Other aspects and novel features of the present invention will become apparent from the following detail description of the invention when considered in conjunction with the accompanying drawings.